On each business day, the South African Reserve Bank (SARB) publishes compounded averages and index values based on past realisations of the South African Overnight Index Average (ZARONIA) interest rate benchmark. Publishing compounded ZARONIA period averages provides market participants with a single point of reference for backward-looking term rates, including 1-week, 1-month, 3-month, 6-month, 9-month, and 12-month tenors.
The ZARONIA index measures the cumulative effect of compounding ZARONIA on a notional unit of investment over time, with the initial value set to 100.000000000000 on 1 November 2022, the first value date of ZARONIA. Market participants may use the published index values to determine the compounded ZARONIA period average rate that is applicable over their maturities of choice.
The SARB publishes the compounded ZARONIA period averages and index at approximately 10H00, South African time. The calculation methodology and policies governing compounded ZARONIA period averages can be found here.